Phenotypes associated with this allele

• Allele Symbol: Mesp2^tm1Ysa
• Allele Name: targeted mutation 1, Yumiko Saga
• Allele ID: MGI:2137558
• Summary: 5 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Mesp2^tm1Ysa/Mesp2^tm1Ysa	either: (involves: C57BL/6 * CBA) or (involves: C57BL/6 * CBA * ICR)	MGI:3702287
hm2	Mesp2^tm1Ysa/Mesp2^tm1Ysa	involves: C57BL/6 * CBA	MGI:2386773
ht3	Mesp2^tm1Ysa/Mesp2^tm7(mespb)Ysa	involves: C57BL/6 * CBA	MGI:3702281
ht4	Mesp2^tm1Ysa/Mesp2^tm7.1(mespb)Ysa	involves: C57BL/6 * CBA	MGI:3702284
cx5	Mesp2^tm1Ysa/Mesp2^tm10Ysa Gt(ROSA)26Sor/?	involves: 129 * C57BL/6 * CBA	MGI:3709491

Genotype
MGI:3702287

hm1

• Allelic Composition: Mesp2^tm1Ysa/Mesp2^tm1Ysa
• Genetic Background: either: (involves: C57BL/6 * CBA) or (involves: C57BL/6 * CBA * ICR)

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

mortality/aging

neonatal lethality, complete penetrance ( J:42014 )

• die within 20 minutes of birth

growth/size/body

decreased body length ( J:42014 )

• short, tapered trunk

limbs/digits/tail

vestigial tail ( J:42014 )

embryo

abnormal rostral-caudal patterning of the somites ( J:42014 )

• at E10.5 in the prospective cervical region, no clear difference is seen between the rostral and caudal parts of the sclerotome , although somitic boundaries are present

• at E10.5 in the prospective thoracolumbar region, both rostral-caudal polarity and clear segment boundaries are absent

abnormal paraxial mesoderm morphology ( J:42014 )

• at E9.0 defective segmentation is seen in the paraxial mesoderm in the presumptive cervicothoracic region

• at E9.5 differentiation of the somitic mesoderm into the dermomyotome and sclerotome occurs without segmentation of the paraxial mesoderm

spina bifida ( J:42014 )

• poorly formed vertebral lamina in the lumbosacral region result in spina bifida

abnormal somite border morphology ( J:42014 )

• at E10.5 in the prospective thoracolumbar region, clear boundaries between the somites are absent in the sclerotome

delayed somite formation ( J:42014 )

• segmentation of paraxial mesoderm is delayed but not completely blocked

incomplete somite formation ( J:42014 )

• at E10.5 in the prospective thoracolumbar region, clear boundaries between the somites are absent in the sclerotome

• however, segmentation is seen in the dermatome and myotome

skeleton

rib fusion ( J:42014 )

• proximal regions of the ribs are fused

absent intervertebral disk ( J:42014 )

• unidentifiable

abnormal vertebrae morphology ( J:42014 )

• vertebral bodies appear amorphous and alignment of ossification centers is irregular

abnormal vertebral lamina morphology ( J:42014 )

• poorly formed in the lumbosacral region resulting in spina bifida

vertebral fusion ( J:42014 )

• segmentation of the lateral structures of the vertebrae is totally lost

• however, segmentation of the ventral structures is weakly retained

cervical vertebral fusion ( J:42014 )

• the atlas and axis are always fused

• however, the joint between the occipital bone and the atlas is normal

lumbar vertebral fusion ( J:42014 )

• fusion of the transverse processes

fusion of vertebral arches ( J:42014 )

• fusion of the pedicles of the neural arches

abnormal sclerotome morphology ( J:42014 )

• impaired segmentation especially in evident at E12.5 in the caudal part of the embryo

• impairment of segmentation is more severe in the sclerotome than in the dermomyotome

nervous system

abnormal axon extension ( J:42014 )

• at E10.5 in the prospective thoracolumbar region, spinal nerve axonal outgrowth into the ventral sclerotome is strongly impaired and fusion of disturbed axons is seen

• however, development of cranial nerves is similar to wild-type

spina bifida ( J:42014 )

• poorly formed vertebral lamina in the lumbosacral region result in spina bifida

fused dorsal root ganglion ( J:42014 )

• fused and located more dorsally compared to wild-type controls

muscle

muscle phenotype ( J:42014 )

N • no particular abnormalities are found in the muscle and muscle fiber alignment is normal

abnormal dermomyotome development ( J:42014 )

• delayed and irregular segmentation

integument

integument phenotype ( J:42014 )

N • no particular abnormalities are found in the dermis

cellular

abnormal axon extension ( J:42014 )

• at E10.5 in the prospective thoracolumbar region, spinal nerve axonal outgrowth into the ventral sclerotome is strongly impaired and fusion of disturbed axons is seen

• however, development of cranial nerves is similar to wild-type

Genotype
MGI:2386773

hm2

• Allelic Composition: Mesp2^tm1Ysa/Mesp2^tm1Ysa
• Genetic Background: involves: C57BL/6 * CBA

embryo

abnormal somite development ( J:75945 )

abnormal somite border morphology ( J:75945 )

• absence of segmental borders in embryonic tails at E11.5

absent somites ( J:75945 )

• absence of epithelial somites in embryonic tails at E11.5

Genotype
MGI:3702281

ht3

• Allelic Composition: Mesp2^tm1Ysa/Mesp2^{tm7(mespb)Ysa}
• Genetic Background: involves: C57BL/6 * CBA

embryo

abnormal somite development ( J:75945 )

• at E11.5 in embryonic tails, initial segmental borders form; however, segregation is incomplete and somitic cells remain between the newly formed somites

• maintenance of segmental borders is impaired

• failure of segregation is most severe in these embryos compared to mice either homozygous for the knock-in allele or carrying one allele with the neo cassette removed

abnormal rostral-caudal patterning of the somites ( J:75945 )

• expression analysis indicates impaired formation of rostral-caudal polarity in the anterior presomitic mesoderm

• severity of impairment is less than in homozygous null mice

abnormal somite border morphology ( J:75945 )

• maintenance of segmental borders is impaired

skeleton

rib fusion ( J:75945 )

• fusion of both the ribs and vertebral column, although not as severe as in homozygous null mice

• fusions are more severe than in mice where the neo cassette has been removed by Cre-mediated recombination

vertebral fusion ( J:75945 )

• fusion of both the ribs and vertebral column, although not as severe as in homozygous null mice

• fusions are more severe than in mice where the neo cassette has been removed by Cre-mediated recombination

Genotype
MGI:3702284

ht4

• Allelic Composition: Mesp2^tm1Ysa/Mesp2^{tm7.1(mespb)Ysa}
• Genetic Background: involves: C57BL/6 * CBA

mortality/aging

neonatal lethality, complete penetrance ( J:75945 )

• die shortly after birth

embryo

abnormal somite development ( J:75945 )

• at E11.5 in embryonic tails, initial segmental borders form; however, segregation is incomplete and somitic cells remain between the newly formed somites

abnormal rostral-caudal patterning of the somites ( J:75945 )

• expression analysis indicates impaired formation of rostral-caudal polarity in the anterior presomitic mesoderm

• severity of impairment is less than in homozygous null mice or in mice where the neo cassette had not been removed

abnormal somite border morphology ( J:75945 )

• maintenance of segmental borders is impaired

skeleton

rib fusion ( J:75945 )

• fusion of both the ribs and vertebral column, although not as severe as in homozygous null mice or as in mice where the neo cassette had not been removed

vertebral fusion ( J:75945 )

• fusion of both the ribs and vertebral column, although not as severe as in homozygous null mice or as in mice where the neo cassette had not been removed

Genotype
MGI:3709491

cx5

• Allelic Composition: Mesp2^tm1Ysa/Mesp2^tm10Ysa; Gt(ROSA)26Sor/?
• Genetic Background: involves: 129 * C57BL/6 * CBA

embryo

failure of somite differentiation ( J:120635 )

• epithelial somites do not form and the entire somatic mesoderm is caudalized

• however, dermamyotome and sclerotome differentiation is unaffected